The invention relates to a sensor arrangement comprising at least one sensor, which may be so attached by means of an attachment means to the outside of a carrying part that the attachment means encompasses the carrying part for at least 180xc2x0 of its peripheral extent.
Such a sensor arrangement is for example disclosed in the German utility model number 29,717,492.2. Here an attachment means is provided as an attachment ring or attachment clip, which is able to be secured coaxially to the outer periphery of a carrying part formed by the housing of a fluid power cylinder and possesses a holding groove, into which a sensor is fitted in a detachable fashion. The sensor serves for sensing the position of a piston, which is arranged in a moving manner in the interior of the carrying part, of the fluid power cylinder.
The exact adjustment of the sensor arrangement on the outer periphery of the carrying part is relatively complex in this known case. On the one hand the attachment means must be fixed in a suitable position on the carrying part and on the other hand it is necessary to secure the sensor in a suitable relative position on the carrying part. A further point is that the known sensor arrangement makes extremely large dimensions necessary in the radial direction in order to render possible reliable attachment of the sensor on the attachment means.
One object of the present invention is to provide a sensor arrangement which possesses a simpler structure and may be fitted in place more readily.
In order to achieve this aim there is the provision that the sensor is designed in the form of a non-separable, integral component of the attachment means.
It is in this manner that the association between the sensor and the attachment means is predetermined as a manufacturer""s setting so that the user merely has to fix the attachment means at the desired position of a carrying part in order to position the sensor in a manner in accordance with requirements. The attachment means and the sensor then constitute a non-separable integral unit, which during production makes possible a reduction in costs and simultaneously allows keeping to very compact dimensions. Although the sensor arrangement is able to be employed completely universally, it is particularly advantageous in connection with detecting the position of the drive unit of a linear drive adapted to be actuated by fluid force and/or electrically, if the sensor arrangement may be secured in a favorable manner on the outer periphery of the housing of the linear drive. It is convenient for the attachment means to be able to be clamped at a suitable position on the carrying part and so may be extremely adaptably reset in position.
Advantageous further developments of the invention will appear from the dependent claims.
In the case of an advantageous design the attachment means is at least partly and preferably totally designed to be bendingly flexible, it furthermore being possible for it to have resiliently elastic properties to customize it to the needs of the particular user. More particularly in this connection it is an advantage for the attachment means to consist of plastic material, which more especially permits an extremely simple integration of the sensor directly during the production of the attachment means.
The attachment means may be designed in the form of an attachment clip, which fits around the carrying part, when mounted on same, along part of the periphery, the necessary holding force being able to be produced for instance by a detent or snap action connection. Thus there is the possibility of designing the attachment clip in such a flexibly elastic fashion that it may be snap fitted on the carrying part after firstly opening it out and slipping it in place. This design is more particularly to be preferred when the carrying part is not accessible over its full periphery.
In a further design there is a provision such that the attachment means is designed in the form of an attachment ring, which surrounds the carrying part completely when mounted thereon. It is in this manner that a particularly reliable attachment on the carrying part is rendered possible. In order to provide the necessary clamping force the attachment means may be interrupted at a point on its periphery with the formation of two clamping arms, the clamping arms being able to be so braced in relation to one another using a suitable clamping means, which for instance is designed in the form of a detent means, that the attachment means surround the carrying part with a firm seat thereon. The attachment means may in this case more particularly be designed like a hose clip.
More particularly when the sensor means is to be suitable for selective attachment to carrying parts of different diameter, it is an advantage if not only the attachment means itself but also furthermore the sensor integrated in it possesses bendingly flexible properties and accordingly may be adapted to surfaces of carrying parts with different degrees of curvature without any chance of damage. The sensor may for example have a bendingly flexible printed circuit board having the necessary electrical and electronic components.
In the case of a further convenient design of the sensor arrangement there is a provision such that the sensor is in the form of a part incast in the material of the attachment means, that is to say it is practically incast in the attachment means. This offers the possibility of so embedding the sensor in the attachment means that it is at least mostly surrounded by the material of the attachment means and is also protected against mechanical effects.
More particularly when the part to be provided with the sensor arrangement is subject to substantial vibrations, it is an advantage for the attachment means to be provided with a securing element, projecting from the side facing the carrying part, which element may be caused to bite into the surface of the carrying part at least to a small extent in order, in addition to the friction connection produced by the attachment means, to get a securing action based on interlocking contact.
In the following the invention will be described with reference to the drawing.